Sixteen-membered macrolide compounds produced by Streptomyces have the properties of high activity and broad spectrum, and are widely applied to prevent and control insect pests and mites of agriculture and forestry. Such compounds have been developed into a plurality of pesticide products, such as avermectin, emamectin benzoate, and milbemycin etc., and occupy bigger pesticide market shares. Such compounds bind to soil tightly in natural environment, and are difficult to be washed out and to infiltrate. The compounds can be rapidly degraded into inactive compounds under light or by soil microorganisms. The molecular fragments of the compounds will finally be decomposed and utilized by plants and microorganisms as carbon source, with no residual toxicity. Such compounds have already become a highly efficient biological pesticide for agricultural and veterinary use.
Due to the outstanding properties of such compounds, comprehensive researches have been carried out in domestic and abroad on their homologs. The researchers has been trying to modify the molecular structure via chemical synthesis or mutate the producing strain through genetic modification, so as to obtain novel compounds with higher activity. Thousands of compounds have already been synthesized through molecular structure modification, some of which are commercially available now, including ivermectin, emamectin, doramectin, eprinomectin and selamectin etc. The modified compounds have overcome some disadvantages of their parent compounds, and are further improved in terms of the range of prevention and control, the insecticidal activity and the toxicity to human, animals and environment. However, the activity of such compounds still can not satisfy the requirement of actual situation.